Home grown tomatoes taste better but help from warm water is on the way for the supermarket lot

Important news from the 250th National Meeting & Exposition of the American Chemical Society (ACS) held this week. Help is at hand to restore flavour to supermarket tomatoes.

Among the 9,000 or so reports on new advances in science and other topics presented at the meeting was one by Jinhe Bai, Ph.D. and his colleagues at the U.S. Department of Agriculture, Agricultural Research Service, and the University of Florida on ways of improving the taste of mass marketed tomatoes.

"Ideally, tomatoes should be picked ripe and then sold immediately, as they are at farm stands," Dr Bai explained. But this isn't always possible for commercially sold tomatoes, which are often stored and then shipped over long distances. To prevent tomatoes from becoming too ripe before they reach the store, growers pick them when they are still green. Packers then use a gas called ethylene to trigger fruit ripening, and after that the tomatoes are stored and shipped at low temperatures.
The problem is that chilling tomatoes degrades their flavor, said Bai in a press release explaining his research.

In an effort to improve the flavor quality, his team developed a slightly different method. "To produce a better tasting tomato, we added a hot water pre-treatment step to the usual protocol that growers follow," he explains. "We found that this pre-treatment step prevents flavor loss due to chilling."
Describing the process in more detail, Bai explains that he and his colleagues at the U.S. Department of Agriculture, Agricultural Research Service, and the University of Florida dipped Florida-grown green tomatoes in hot water (about 125 degrees Fahrenheit) for five minutes and then let them cool at room temperature. Next they chilled the fruit to between 41 and 55 degrees Fahrenheit, the temperatures commercial producers use for shipping. After the tomatoes fully ripened, the researchers tested them for flavor and aroma.
They found that tomatoes heated before chilling had higher levels of flavor compounds (6-methyl-5-hepten-2-one, 2-methylbutanal and 2-phenylethanol) than non-heated fruit, and they tasted better, Bai says. "Chilling suppresses production of oxygen, nitrogen and sulfur-containing heterocyclic compounds, ketones, alcohols and aldehydes, including 13 important aroma components of tomato flavor. But hot water-treated fruit actually produced higher concentrations of these important aroma contributors, even with subsequent chilling."
Currently, they are monitoring flavor compounds at additional time points -- when the tomatoes are green, soon after the process is performed and when they are partially ripened. This information will be combined with data on fully ripened tomatoes to help the team develop a better commercial process.